SEA-ME/piracer_py

PiRacer-Py

This package will provide you with a simple abstraction layer for the PiRacer development platform. You will be able to control the powertrain and the steering as easy as possible.

I also provides an easy way to grab images from the camera (based on v4l2 and opencv)

PiRacer Standard and Pro architecture overview:

Install

Tested on the following Hardware:

• Raspberry Pi 4 Model B 4GB

Tested on the following distributions:

• Raspberry Pi OS Lite "Bullseye" (64-Bit)
  • Camera is not working at the moment
• Ubuntu Server 22.04.1 LTS (64-Bit)
• Ubuntu Server 20.04.5 LTS (64-Bit)

Add additional sources (Ubuntu only)

If you run Ubuntu, add the following sources first:

sudo -s
echo "deb http://archive.raspberrypi.org/debian/ buster main" >> /etc/apt/sources.list
apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 7FA3303E
apt update
exit

If you're facing messages like the following when trying to install packages via apt:

pi@ubuntu:/home/pi# sudo apt install PACKAGES...
Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 1807 (unattended-upgr)

Disable the unattended upgrade feature by running the following command to disable:

sudo dpkg-reconfigure unattended-upgrades

Install dependencies:

sudo apt update
sudo apt install \
    gcc \
    v4l-utils \
    i2c-tools \
    raspi-config \
    python3-dev \
    python3-setuptools \
    python3-venv \
    libopencv-dev

Setup periphery

Mount boot partition (Ubuntu only)

On Ubuntu it is necessary to explicitly mount the boot partition before enabling the i2c controller and camera:

mount /dev/mmcblk0p1 /boot/

Enable i2c and camera

Use the raspi-config tool to enable the following peripherals:

• i2c: Interface Options > I2C
• Camera: Interface Options > Camera

Afterwards, reboot:

sudo reboot

Install piracer-py package

cd ~
mkdir piracer_test/
cd piracer_test/
python3 -m venv venv
source venv/bin/ativate

pip install piracer-py

Examples

The following examples will show the basic functionality of the piracer-py package. Make sure the virtual environment from step Install piracer-py package is activated.

Basic example

This basic example will test the power train and the steering.

Paste the following code into basic_example.py

import time
from piracer.vehicles import PiRacerPro

if __name__ == '__main__':

    piracer = PiRacerPro()
    # piracer = PiRacerStandard()

    # Forward
    piracer.set_throttle_percent(0.2)
    time.sleep(2.0)

    # Brake
    piracer.set_throttle_percent(-1.0)
    time.sleep(0.5)
    piracer.set_throttle_percent(0.0)
    time.sleep(0.1)

    # Backward
    piracer.set_throttle_percent(-0.3)
    time.sleep(2.0)

    # Stop
    piracer.set_throttle_percent(0.0)

    # Steering left
    piracer.set_steering_percent(1.0)
    time.sleep(1.0)

    # Steering right
    piracer.set_steering_percent(-1.0)
    time.sleep(1.0)

    # Steering neutral
    piracer.set_steering_percent(0.0)

Run it with:

python basic_example.py

Remote control example

The following example will let you control the PiRacer with the ShanWan Gamepad that is shipped with the PiRacer package. Make sure the dongle is connected to your Raspberry Pi.

Paste the following code into rc_example.py:

from piracer.vehicles import PiRacerPro
from piracer.gamepads import ShanWanGamepad

if __name__ == '__main__':

    shanwan_gamepad = ShanWanGamepad()
    piracer = PiRacerPro()
    # piracer = PiRacerStandard()

    while True:
        gamepad_input = shanwan_gamepad.read_data()

        throttle = gamepad_input.analog_stick_right.y * 0.5
        steering = -gamepad_input.analog_stick_left.x

        print(f'throttle={throttle}, steering={steering}')

        piracer.set_throttle_percent(throttle)
        piracer.set_steering_percent(steering)

Run it with:

python rc_example.py

Grab images example

With the following example you can grab and save images from the Raspberry Pi camera.

Paste the following code into camera_grab_example.py:

import cv2
from piracer.cameras import Camera, MonochromeCamera

if __name__ == '__main__':
    camera = MonochromeCamera()

    image = camera.read_image()
    cv2.imwrite('image.png', image)

Run it with:

python camera_grab_example.py